【作者】 吴加军；

【导师】 强胜；

【作者基本信息】 南京农业大学 ， 植物学， 2006， 硕士

【摘要】 化学除草已成为全球性现代化农业生产的重要组成部分，但是随着除草剂的大量反复使用，导致越来越多的杂草对除草剂产生抗药性。抗药性杂草种群在全球范围的迅速发展和蔓延，给以化学防治为主体的杂草综合防治体系提出了新的课题。由于草甘膦是全球使用范围最广、用量最大的灭生性除草剂，人们对其抗（耐）性杂草问题格外关注。由于草甘膦的独特性质，如作用机制、代谢、化学结构和无土壤残留活性，一般认为杂草对其难以产生抗药性。直到1990年，还认为杂草对草甘膦的抗药性不是问题。但是，在使用15年后，1996年才首次在澳大利亚、南非与美国加州发现了瑞士黑麦草的抗性群体，而且，有越来越多之势。1999年智利中部农民报告，果园使用草甘膦8～10年后，多花黑麦草（Lolium multiflorum Lam）的抗性提高了5～6倍；2000年在北美洲抗草甘膦转基因大豆连作3年后，小飞蓬（Conyza Canadensis L）的抗性提高了10倍。随着转基因抗草甘膦作物在全球范围的推广，草甘膦抗药性日益成为一个不可忽视的问题。我国是草甘膦生产大国，也是该除草剂使用的大国，监测杂草抗药性，有助于对抗性杂草种群的产生做出早期预测，建立合理的除草剂轮用体系和杂草综合防治技术体系。也可以为国家杂草控制策略、除草剂生产、推广应用以及转基因抗草甘膦作物的推广应用的宏观控制体系提供基础信息。1、不同剂型草甘膦药剂对杂草的防效差异通过室内生测和野外田间试验，对国内、国外公司生产的有代表性的7种不同剂型的草甘膦产品的除草效果进行了比较。结果表明：由于不同草甘膦药剂的助剂和盐成分不同，它们对杂草的毒害速度和防除效果存在着不同程度的差异，其中以孟山都公司生产的41％草甘膦异丙胺盐水剂（农达）表现最好，对杂草的毒害速度和防除效果均优于其它几种草甘膦剂型，且对不同杂草的药效表现稳定，是用于草甘膦耐性杂草筛选的理想药剂。2、南京地区耐草甘膦杂草种群的调查用41％农达250ml／667m²、500ml／667m²、1000ml／667m²三个剂量处理南京地区不同生境的杂草种群，检测不同类型杂草对草甘膦的敏感程度。结果发现，多年生的菊科、蓼科、葡萄科和部分多年生禾本科杂草对草甘膦具有较强的耐药性，同种杂草成株的耐药程度明显高于苗期。同时对部分不同耐受程度杂草的ED₉₀值进行了测定。结果表明敏感杂草的致死浓度在150ml／667m²～250ml／667m²之间；一般耐受杂草的致死浓度在250～400ml／667m²之间；中等耐受杂草的致死浓度在400～600ml／667m²；高度耐受杂草的致死浓度在600ml／667m²以上。3、抗草甘膦杂草检测方法的建立与主要杂草的抗性筛选采用温室生测法建立小飞蓬对草甘膦的抗性检测方法。首先，将待测小飞蓬的种子进行育苗，当幼苗长至5-7叶期时，单株移栽到口径为5×5cm的塑料口杯中，直至15-20叶期时，施用草甘膦。草甘膦异丙胺盐水剂的浓度设置为：0，35，70，140，280，560，1120，2240，4480，8960 g ai／ha。在用药处理后3d进行第一次观察，记录各浓度的药害症状，并划分药害级别。以后每隔4天记录一次，药害级别转化为药害综合指数。当不同处理间的药害症状有极显著差异时进行鲜重和干重的测定。分别以所获得的药害综合指数、鲜重、干重和药剂剂量的对数进行回归，所有的数据都用log-logistic回归模型进行模拟。通过比较两次重复实验的结果，证实采用药害分级、鲜重、干重的方法都能较好地反映小飞蓬受害情况与不同剂量草甘膦的关系，但药害分级的方法是三种方法中重复性最好的一种。同时用药害分级法对主要杂草种群进行了草甘膦抗性检测，由于这些杂草所在地区的草甘膦施用年限较短，未能发现抗性水平较高的杂草种群，最高相对抗性比值只有2左右。4、抗草甘膦小飞蓬种群的筛选与检测用室内生测法和莽草酸含量检测法对2004年从浙江果园采集的有多年使用草甘膦历史的2个小飞蓬种群（001G、002G）的草甘膦抗性水平进行了测定。结果表明，2个小飞蓬种群均对草甘膦产生了明显的抗性，001G的有效中浓度ED₅₀是2513.043 g ai／ha，002G的有效中浓度是2412.682 g ai／ha，它们与敏感种群的最高相对抗性比值分别为8.28和7.95。莽草酸测定结果也表明，与敏感种群相比，两个抗性种群的莽草酸累积量明显较少，且差异显著。更多还原

【Abstract】 Chemical weed control has been of vital importance in global agriculture modernization. Due to much more frequent use of chemical herbicides, more and more weeds have involved in resistance to herbicides. The burgeoning of herbicide-resistant weed populations has become a new problem to comprehensive weed control system mainly composed of chemical control. The issue of glyphosate-resistant weeds has attracted extensive attention since glyphosate became the most important nonselective herbicide in the world. Owing to unique characteristics of glyphosate such as functional mechanism,metabolization, chemical structure and no soil activity, up to 1990, people have not been aware of weeds resistant to glyphosate. After 15 years’ use of glyphosate,glyphosate-resistant L. multiflorum as the first case was discovered in Australia, South Africa and California in USA in 1998. Since then, glyphosate-resistant cases happened worldwide frequently. In 1999, farmers report from central Chile, the resistance of L.multiflorum was 5-6 times after 8-10 years’ use of glyphosate in orchard. The resistance of Conyza canadensis was 10 times after glyphosate-tolerant transgenic soybean continuously cropping three years in North America in 2000. Glyphosate resistance is becoming a problem which should not be neglected along with the popularization of glyphosate-tolerant transgenic crops. China is one of main countries in use and production of glyphosate. The monitor of weeds resistant to glyphosate is helpful for early forecasting of emergence of resistant weeds populations and establishing systems of rational use of herbicide and comprehensive weed control, also can provide basic information of national weed control, herbicide manufacturing, extention and application as well as macroscopical control system of extention and application of glyphosate-resistant transgenic crops.We bioassayed comparatively the efficacy of seven kinds of glyphosate formulation by greenhouse and field trials. The results showed that the efficacy of these different formulations with various adjuvants and salts against weeds were different significantly. Roundup produced by Monsanto Corporation performed best in both toxicity and efficacy. Roundup also had stable efficacy against different weeds. It is the perfect herbicide to be used in the selection of glyphosate tolerant weeds.We screened the glyphosate-tolerant weeds in Naming. The weeds growing in various habitats and different seasons were treated by Roundup in concentrations: 250ml/667m²,500 ml/667m², 1000 ml/667m². The results showed that the perennial weeds of Compositae,Vitaceae and Gramineae had high glyphosate tolerance. The tolerance of adult weeds was higher than at seedling stage. The ED₉₀ values of the weeds at different tolerance levels also were tested. The results showed that the lethal concentration of sensitive weeds was 150ml/667m²-250ml/667m². That of low tolerant weeds was 250 ml/667m²-400 ml/667m²,that of middle tolerant weeds was 400 ml/667m²-600ml/667m² and the lethal concentration of high tolerant weeds was more than 600ml/667m².The bioassay method was established to monitor glyphosate resistance of weeds. The sampling seeds were sown onto the mixed soil surface of shallow tray, and were cultured to be seedling. Single seedling at 5-7 leaves stage was transplanted into separate 5×5cm plastic cup containing mixed soil. Then the isopropylamine salt of glyphosate at the rate of 0, 35, 70, 140, 280, 560, 1120, 2240, 4480, 8960 g ai/ha were applied when the seedling grew to 15-20 leaves stage. The first observation was carded out three days after application and herbicide injury was recorded based on visual assessment standard. The same work was consistently conducted every four days until the injury symptom did not develop further, and fresh and dry weight of plant above the ground was weighed. All data were fitted to a log-logistic regression model..Through comparison of the results of two-time experiments, it was concluded that three values: herbicide injury index, fresh weight and dry weight all could reflect the relationship between herbicide injury and glyphosate dosage, but the herbicide injury index was the best one by which the results could be repeated very well. And we use it to test weather the weeds collected by ourselves and Syngenta Company could have involved in resistance to glyphosate. But we did not find high glyphosate-resistant level weeds, the highest resistance ratio to susceptible population is about 2. The reason may be the location where we got the weeds was used glyphosate for too short time.We tested the resistance level to glphosate of two horseweed populations （001G, 002G） collected from Zhejiang Province by using bioassay and shikimate acid test. The results showed that both of those two horseweed populations have obvious resistance to glyphosate. The ED₅₀ of 001G was 2513.043 g ai/ha and that of 002G was 2412.682 g ai/ha,and the highest resistance ratios to susceptible population are 8.28 and 7.95. The results of shikimate acid test also showed that the increased quantity of shikimate acid in two resistant populations is obviously lower than that in susceptible population.更多还原